This action would amend certain airworthiness regulations for transport category airplanes to require fuel tank designs that prevent a fuel tank explosion caused by flame propagation through the fuel tank vents from external fires. This action would add a new requirement for fuel tank vent fire protection and would increase the time available for passenger evacuation and emergency response. This proposed amendment would apply to applications for new type certificates and certain applications for amended or supplemental type certificates. It would also require certain airplanes produced in the future and operated by air carriers to meet the new standards.